CODEWITHSUNDEEP
postgresqlsequencepsql
user9975442
user9975442

Reputation:

PostgreSQL sequence connects to columns

So im working on a database at the moment, and i can see there are loads of sequences. I was wondering how sequences link up to their corresponding column in order to increment the value.

for example if i create a new table with a column names ID how would i apply a sequence to that column.

Upvotes: 1

Views: 1604

Answers (1)

Erwin Brandstetter
Erwin Brandstetter

Reputation: 656882

Typically, sequences are created implicitly. With a serial column or (alternatively) with an IDENTITY column in Postgres 10 or later. Details:

Sequences are separate objects internally and can be "owned" by a column, which happens automatically for the above examples. (But you can also have free-standing sequences.) They are incremented with the dedicated function nextval() that is used for the column default of above columns automatically. More sequence manipulation functions in the manual.

Details:

Or you can use ALTER SEQUENCE to manipulate various properties.

Privileges on sequences have to be changed explicitly for serial columns, while that happens implicitly for the newer IDENTITY columns.

Upvotes: 1

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